Qiao, Wanjin; Qiao, Yu; Liu, Fulu; Zhang, Yating; Li, Ran; Wu, Zhenzhou; Xu, Haijin; Saris, Per Erik Joakim; Qiao, Mingqiang published the artcile< Engineering Lactococcus lactis as a multi-stress tolerant biosynthetic chassis by deleting the prophage-related fragment>, Electric Literature of 492-62-6, the main research area is proteomics rpsN rplR lysozyme carbohydrate Lactococcus; Genome editing; Lactococcus lactis; Multi-stress tolerance; Nisin immunity; Nisin yield; Prophage-related fragment; TMT quantitative proteomics.
In bioengineering, growth of microorganisms is limited because of environmental and industrial stresses during fermentation This study aimed to construct a nisin-producing chassis Lactococcus lactis strain with genome-streamlined, low metabolic burden, and multi-stress tolerance characteristics. The Cre-loxP recombination system was applied to reduce the genome and obtain the target chassis strain. A prophage-related fragment (PRF; 19,739 bp) in the L. lactis N8 genome was deleted, and the mutant strain L. lactis N8-1 was chosen for multi-stress tolerance studies. Nisin immunity of L. lactis N8-1 was increased to 6500 IU/mL, which was 44.44% higher than that of the wild-type L. lactis N8 (4500 IU/mL). The survival rates of L. lactis N8-1 treated with lysozyme for 2 h and lactic acid for 1 h were 1000- and 10,000-fold higher than that of the wild-type strain, resp. At 39°C, the L. lactis N8-1 could still maintain its growth, whereas the growth of the wild-type strain dramatically dropped. SEM showed that the cell wall integrity of L. lactis N8-1 was well maintained after lysozyme treatment. Tandem mass tags labeled quant. proteomics revealed that 33 and 9 proteins were significantly upregulated and downregulated, resp., in L. lactis N8-1. These differential proteins were involved in carbohydrate and energy transport/metabolism, biosynthesis of cell wall and cell surface proteins. PRF deletion was proven to be an efficient strategy to achieve multi-stress tolerance and nisin immunity in L. lactis, thereby providing a new perspective for industrially obtaining engineered strains with multi-stress tolerance and expanding the application of lactic acid bacteria in biotechnol. and synthetic biol. Besides, the importance of PRF, which can confer vital phenotypes to bacteria, was established.
Microbial Cell Factories published new progress about Carbohydrates Role: BSU (Biological Study, Unclassified), BIOL (Biological Study). 492-62-6 belongs to class alcohols-buliding-blocks, and the molecular formula is C6H12O6, Electric Literature of 492-62-6.
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